Curved wood panels are used in backrests for wooden chairs, casket lids, boat shells, and wood furniture, cabinet doors and drawers, to only give some examples. Some curved wood panels, such as the backrests of chairs, are folded on the length of the grain, i.e. longitudinally arched. We can say that other curved wood panels such as casket lids, have boards parallel to the axis of the vault, i.e. are transversely arched.
The production of longitudinally arched wood panels implies folding, or curving, the wood. Curving or folding wood is a delicate operation which requires to master the process and to have a good knowledge of the solid wood properties. The green wood, that is wood freshly cut, is generally easier to curve then the wood which was dried in an oven. The wood can be exposed to vapor, or be immersed in the water, before it is curved to reduce the probability of checking or cracking. Curving the wood can be made by different ways, for example using a custom jig or using a press.
The production of longitudinally arched wood panels implied, until this day, assembling several parts previously curved side by side, by any way, to form a panel. For the transversely curved panels, the machining of at least one edge of each of the wood boards is necessary to give it an angle to assemble the boards, and to assemble them to give them a transversely shaped curve. The radius of the vault is thus predetermined by the angle at which the edges of the wood parts are machined.
Curving or folding solid wood by vapor has allowed so far the use of parts of wood of a single cut, that is, unique parts, which have to have at the onset the wished final dimension. This thus limits the dimension of the possible curved parts and often causes a lot of wood loss.
The known processes of production to obtain curved solid wood panels were satisfactory to a certain extent. However, there is still place for improvement.